android: Allow opening in-emulation menu by pressing Back (#6248)

It seems like the menu isn't showing up for users on Android 13.
We're not sure what's wrong, and the approach we've been using for the
menu hasn't been entirely reliable in the past either (in particular
not on non-mobile form factors like Chromebooks and VR devices),
so let's make it possible to open the menu by pressing Back,
an action that works reliably on most kinds of Android devices.
(Not sure if there's an equivalent of Back on devices like watches,
but I think we can pretty safely ignore those for now.)

src/android/app/src/main/java/org/citra/citra_emu/activities/EmulationActivity.java

@@ -12,6 +12,7 @@ import android.view.InputDevice;
 import android.view.KeyEvent;
 import android.view.LayoutInflater;
 import android.view.Menu;
+import android.view.MenuInflater;
 import android.view.MenuItem;
 import android.view.MotionEvent;
 import android.view.SubMenu;
@@ -19,11 +20,13 @@ import android.view.View;
 import android.widget.CheckBox;
 import android.widget.SeekBar;
 import android.widget.TextView;
+import android.widget.Toast;
 
 import androidx.annotation.IntDef;
 import androidx.annotation.NonNull;
 import androidx.appcompat.app.AlertDialog;
 import androidx.appcompat.app.AppCompatActivity;
+import androidx.appcompat.widget.PopupMenu;
 import androidx.core.app.NotificationManagerCompat;
 import androidx.fragment.app.FragmentActivity;
 
@@ -74,6 +77,7 @@ public final class EmulationActivity extends AppCompatActivity {
     public static final int MENU_ACTION_JOYSTICK_REL_CENTER = 15;
     public static final int MENU_ACTION_DPAD_SLIDE_ENABLE = 16;
     public static final int MENU_ACTION_OPEN_CHEATS = 17;
+    public static final int MENU_ACTION_CLOSE_GAME = 18;
 
     public static final int REQUEST_SELECT_AMIIBO = 2;
     private static final int EMULATION_RUNNING_NOTIFICATION = 0x1000;
@@ -114,6 +118,8 @@ public final class EmulationActivity extends AppCompatActivity {
                 EmulationActivity.MENU_ACTION_DPAD_SLIDE_ENABLE);
         buttonsActionsMap
                 .append(R.id.menu_emulation_open_cheats, EmulationActivity.MENU_ACTION_OPEN_CHEATS);
+        buttonsActionsMap
+                .append(R.id.menu_emulation_close_game, EmulationActivity.MENU_ACTION_CLOSE_GAME);
     }
 
     private View mDecorView;
@@ -223,21 +229,12 @@ public final class EmulationActivity extends AppCompatActivity {
 
     @Override
     public void onBackPressed() {
-        NativeLibrary.PauseEmulation();
+        View anchor = findViewById(R.id.menu_anchor);
-        new AlertDialog.Builder(this)
+        PopupMenu popupMenu = new PopupMenu(this, anchor);
-                .setTitle(R.string.emulation_close_game)
+        onCreateOptionsMenu(popupMenu.getMenu(), popupMenu.getMenuInflater());
-                .setMessage(R.string.emulation_close_game_message)
+        updateSavestateMenuOptions(popupMenu.getMenu());
-                .setPositiveButton(android.R.string.yes, (dialogInterface, i) ->
+        popupMenu.setOnMenuItemClickListener(this::onOptionsItemSelected);
-                {
+        popupMenu.show();
-                    mEmulationFragment.stopEmulation();
-                    finish();
-                })
-                .setNegativeButton(android.R.string.cancel, (dialogInterface, i) ->
-                    NativeLibrary.UnPauseEmulation())
-                .setOnCancelListener(dialogInterface ->
-                    NativeLibrary.UnPauseEmulation())
-                .create()
-                .show();
     }
 
     @Override
@@ -271,6 +268,10 @@ public final class EmulationActivity extends AppCompatActivity {
         }
     }
 
+    public void onEmulationStarted() {
+        Toast.makeText(this, getString(R.string.emulation_menu_help), Toast.LENGTH_LONG).show();
+    }
+
     private void enableFullscreenImmersive() {
         // It would be nice to use IMMERSIVE_STICKY, but that doesn't show the toolbar.
         mDecorView.setSystemUiVisibility(
@@ -285,7 +286,12 @@ public final class EmulationActivity extends AppCompatActivity {
     @Override
     public boolean onCreateOptionsMenu(Menu menu) {
         // Inflate the menu; this adds items to the action bar if it is present.
-        getMenuInflater().inflate(R.menu.menu_emulation, menu);
+        onCreateOptionsMenu(menu, getMenuInflater());
+        return true;
+    }
+
+    private void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
+        inflater.inflate(R.menu.menu_emulation, menu);
 
         int layoutOptionMenuItem = R.id.menu_screen_layout_landscape;
         switch (EmulationMenuSettings.getLandscapeScreenLayout()) {
@@ -306,8 +312,6 @@ public final class EmulationActivity extends AppCompatActivity {
         menu.findItem(R.id.menu_emulation_show_fps).setChecked(EmulationMenuSettings.getShowFps());
         menu.findItem(R.id.menu_emulation_swap_screens).setChecked(EmulationMenuSettings.getSwapScreens());
         menu.findItem(R.id.menu_emulation_show_overlay).setChecked(EmulationMenuSettings.getShowOverlay());
-
-        return true;
     }
 
     private void DisplaySavestateWarning() {
@@ -333,12 +337,16 @@ public final class EmulationActivity extends AppCompatActivity {
     @Override
     public boolean onPrepareOptionsMenu(Menu menu) {
         super.onPrepareOptionsMenu(menu);
+        updateSavestateMenuOptions(menu);
+        return true;
+    }
 
+    private void updateSavestateMenuOptions(Menu menu) {
         final NativeLibrary.SavestateInfo[] savestates = NativeLibrary.GetSavestateInfo();
         if (savestates == null) {
             menu.findItem(R.id.menu_emulation_save_state).setVisible(false);
             menu.findItem(R.id.menu_emulation_load_state).setVisible(false);
-            return true;
+            return;
         }
         menu.findItem(R.id.menu_emulation_save_state).setVisible(true);
         menu.findItem(R.id.menu_emulation_load_state).setVisible(true);
@@ -367,7 +375,6 @@ public final class EmulationActivity extends AppCompatActivity {
             saveStateMenu.getItem(info.slot - 1).setTitle(text);
             loadStateMenu.getItem(info.slot - 1).setTitle(text).setEnabled(true);
         }
-        return true;
     }
 
     @SuppressWarnings("WrongConstant")
@@ -480,6 +487,24 @@ public final class EmulationActivity extends AppCompatActivity {
             case MENU_ACTION_OPEN_CHEATS:
                 CheatsActivity.launch(this);
                 break;
+
+            case MENU_ACTION_CLOSE_GAME:
+                NativeLibrary.PauseEmulation();
+                new AlertDialog.Builder(this)
+                        .setTitle(R.string.emulation_close_game)
+                        .setMessage(R.string.emulation_close_game_message)
+                        .setPositiveButton(android.R.string.yes, (dialogInterface, i) ->
+                        {
+                            mEmulationFragment.stopEmulation();
+                            finish();
+                        })
+                        .setNegativeButton(android.R.string.cancel, (dialogInterface, i) ->
+                                NativeLibrary.UnPauseEmulation())
+                        .setOnCancelListener(dialogInterface ->
+                                NativeLibrary.UnPauseEmulation())
+                        .create()
+                        .show();
+                break;
         }
 
         return true;

src/android/app/src/main/java/org/citra/citra_emu/disk_shader_cache/DiskShaderCacheProgress.java

@@ -133,6 +133,8 @@ public class DiskShaderCacheProgress {
             case Complete:
                 // Workaround for when dialog is dismissed when the app is in the background
                 fragment.dismissAllowingStateLoss();
+
+                emulationActivity.runOnUiThread(emulationActivity::onEmulationStarted);
                 break;
         }
     }

src/android/app/src/main/res/layout/activity_emulation.xml

@@ -14,4 +14,10 @@
         android:layout_height="match_parent"
         android:transitionName="image_game_icon" />
 
-</FrameLayout>
+    <View
+        android:id="@+id/menu_anchor"
+        android:layout_width="0dp"
+        android:layout_height="0dp"
+        android:layout_gravity="top|end" />
+
+</FrameLayout>

src/android/app/src/main/res/menu/menu_emulation.xml

@@ -115,4 +115,9 @@
         app:showAsAction="never"
         android:title="@string/emulation_open_settings" />
 
+    <item
+        android:id="@+id/menu_emulation_close_game"
+        app:showAsAction="never"
+        android:title="@string/emulation_close_game" />
+
 </menu>

src/android/app/src/main/res/values/strings.xml

@@ -157,6 +157,7 @@
     <string name="loader_error_invalid_format">Invalid ROM format</string>
 
     <!-- Emulation Menu -->
+    <string name="emulation_menu_help">Press Back to access the menu.</string>
     <string name="emulation_save_state">Save State</string>
     <string name="emulation_load_state">Load State</string>
     <string name="emulation_empty_state_slot">Slot %1$d</string>